PR52665 do not let .ident confuse assembler scan tests

PR52665 do not let .ident confuse assembler scan tests

A branch with a name matching scan-assembler pattern triggers
inappropriate FAIL.

E.g. branch fixups-testsuite and
- gcc.target/i386/pr65871-?.c (scan-assembler-not "test")
- gcc.target/i386/pr41442.c (scan-assembler-times "test|cmp" 2)
etc.

This is a recurring problem as can be seen by some -fno-ident additions
by commits from e.g. Michael Meissner over the years: builtins-58.c,
powerpc/pr46728-?.c

The patch below adds -fno-ident if a testcase contains one of
scan-assembler, scan-assembler-not or scan-assembler-times.

Regression tested on x86_64-unknown-linux on a fixups-testsuite branch
where it fixes several false FAILs without regressions.

gcc/testsuite/ChangeLog

2016-06-18  Bernhard Reutner-Fischer  <aldot@gcc.gnu.org>

        PR testsuite/52665
        * lib/gcc-dg.exp (gcc-dg-test-1): Iterate over _required_options.
        * lib/target-supports.exp (scan-assembler_required_options,
        scan-assembler-not_required_options,
        scan-assembler-times_required_options): Add -fno-ident.
        * lib/scanasm.exp (scan-assembler-times): Fix error message.
        * c-c++-common/ident-0a.c: New test.
        * c-c++-common/ident-0b.c: New test.
        * c-c++-common/ident-1a.c: New test.
        * c-c++-common/ident-1b.c: New test.
        * c-c++-common/ident-2a.c: New test.
        * c-c++-common/ident-2b.c: New test.

From-SVN: r264128